Ferrous alloys and abrasive-resistant articles made therefrom



atentecl Nov. 13, 1951 FERROUS ALLOYS AND ABBASIVE-BE SIST- ANT ARTICLES MADE THEREFBOM David J. Giles, Latrobe, Pa... assignor to llatrobe Electric Steel Company, Latrobe, Pa., a corporation of Pennsylvania No Drawing. Application October 7, 1950, Serial No. 189,067

1'! Claims. (CE. 75-126) This invention relates to ferrous alloysand in particular to ferrous alloys having high resistance to abrasion. There has long been a need for steels having a materially greater resistance to abrasion than those commercially available. A good example is steel for use in the fabrication of brick mold liners, tile dies, lamination dies, and other articles which are subject to considerable abrasion and are thereby rapidly worn to a point where they can no longer meet required tolerances in the industry and must be resurfaced or otherwise brought back to the required tolerance. Brick mold liners in which green clay is shaped into bricks are subject to extreme abrasion by the recurrent movement of clay along the faces of the liners. This means that the liners gradually become oversize as well as being roughened so that the shaped brick are outside acceptable tolerances and cannot be freely expelled from the mold.

Since the tolerances on most industrial types of brick are very close this means that the liners must be periodically removed and refinished to size or replaced with the attendantloss of production. The alloys which are presently available have exhibited an undesirably short life.

Considering only the essential elements of my alloy. the preferred analysis for most abrasionresisting applications is:

The composition of my alloy may, however. extend over a relatively wide range and still retain its desirable abrasive resistance. It may include In alloys forusev in installations such as are described above in which the metal is subject to continual or recurring abrasion, it is desirable that they be forgeable and hardenable and yet resist the action of abrasive substances. Historically, the search for alloys having certain desirable properties, has led to various combinations of alloying elements including combinations with vanadium. I have found, however, that while the general trend in vanadium alloys of steel has been in the direction of greater hardenability this is not alone the answer to the problem of abrasion resistance.

I have discovered an alloy having satisfactory forgeability and hardenability which can be made abrasive-resistant by properly controlling the carbon and vanadium content in a manner described in my copending application Serial No. 91,002, now abandoned, filed May 2, 1949, of which this is a continuation in part, and later to be described in this application without materially altering its forgeability and hardenability.

My invention provides an abrasion-resisting alalloying elements such as nickel, tungsten and cobalt in restricted amounts without detrimentally affecting the ability of the alloy to resist abrasion. The composition may fall within the following range of concentrations of alloying elements:

Cr 11 %:to 14% Mn 1% maximum Mn Lessthan 1.5% V 3% to 12% Si 1% maximum Ni Less than 3% W Lessthan 3% Co Less than 5% Balance substantially iron with residual impu- Percent C 2.3 to 2.6 Cr 12.5 to 13.75 V 3 to 5 s1 0.2 to 0.6 Mn o 25 to 0.6 Mo 1 to 1.2

Balance substantially iron with residual impurities in ordinary amounts.

While I have given specific silicon and manganese ranges in the composition of my alloy, these concentrations are the concentrations which normally result from the raw materials which I have used and may accordingly vary tion with respect to alloy A (18-4-1 tool steel). These figures are also given in Table 111.

Table III Per Cent Abrasion I 1 Per cent removed by abrasion as compared with 1 Per cent removed by abrasion u compared with A1133; D.

oy A-calculated values.

Table IV Alloy 0 Cr W V Mo Si Mn Ni Co 2. 42 3. 92 l. 04 52 44 Balance substantially Fe. 2. 40 4. 09 1. 17 66 46 2. 79 Do. 2.35 4.02 1.14 58 .43 Do. 2. 50 4. 08 l. 26 68 50 5. 00 D0. 1.31 3. 74 1.03 .33 .44 Do. i. 42 3. 74 l. 02 30 42 Do. 3.13 4. 08 1.14 61 45 D0. 3. 57 8. 70 l. 08 42 59 Do. 3. 85 11. 64 1. 06 42 59 D0.

forgeable and is air hardening as well as being abrasive-resistant. II it is desired to produce an alloy having similar abrasion resistance and forgeability but at a reduced cost and for use where air hardening is not necessary, the molybdenum may be omitted without materially afiecting the other desirable properties.

In order to illustrate the abrasive resistance oi! my new alloy several heats were made within the range of composition specified above for my new alloy. The abrasion resistance of these alloys of my invention and of the two principal alloy steels previously used for making brick mold liners were compared with the abrasion resistance of an 18-4-1 tool steel taken as a standard 01 100% abrasion. The results of these abrasion tests on forged and hardened pieces one inch in diameter are tabulated below along with a tabulation of chemical composition:

Careful comparison of the composition of the test pieces and their resistance to abrasion shows the superiority of the alloy of my invention over the alloys now used for applications requiring abrasion resistance as well as its superiority over standard 18-4-1 tool steel. Each of the alloys previously used has lost about nine times as much material as the alloy (alloy D) of my invention while the tool steel standard shows more than eight times as much loss of material as does my alloy.

Comparative tests of the abrasion resistance of my alloy as compared with alloys previously used have shown a marked superiority of alloys made according to this invention with respect to their resistance to abrasion. Tests of the abrasion resistance of my alloy as compared with the alloys previously used in brick mold liners were made under conditions of actual u'se'in which one-half of a brick mold liner was made of my Table I alloy (alloy D) while the other half was made of Percent an alloy of the type B. The liner was removed Abrasion 1 when the portion made from alloy B had abraded Alloy A (Standard) 100 to a'point where satisfactory bricks could no Alloy B 109 longer be produced even though the half of the Alloy 107 liner made of alloy D was still in good condition. A1101? D 12 Measurements indicated that alloy B had abraded Percent removed by abralion. away more than twice as much as had alloy D.

Table II Alloy 0 Cr W V Mo Si Mn Ni Co .74 4.10 18.00 1.10 .30 .25 25 Balance substantially Fe. 1.52 12.00 1.00 .75 .30 .30 Do. an 1275 .25 .40 .40 Do. 2.42 1153 3.02 1.04 .52 .44 Do.

In another test an alloy according to this invention was used as side liners in brick molds. The calculated average wear per liner per one thousand bricks on the alloy of this invention was .0011" while the calculated average wear for the previously used material was .0028" indicating that the alloy of this invention was more to give a comparative figure for each modifica- 7 than two and one-half times better than the material heretofore used. In a third test the alloy of this invention was compared with the same material in making refractory brick. In this test the average wear for the alloy of this invention as compared with the alloy previously used was 36% indicating that the alloy of this invention was almost three times as good as the usual material for this purpose. Similar tests on other refractory materials have shown similar remarkable abrasion resistance in the alloy of this invention.

- Peculiarly, the addition of excess carbon and vanadium in excess of 1% in the ratio of 4.2 vanadium to 1 carbon although increasing the abrasion resistance to a remarkable extent has little or no eifect on the forgeability or harden ability of my alloy over those same physical properties of an alloy without such excess carbon and vanadium. For example, the Rockwell C hardness of alloy D and alloy B are substantially identical, as are their forging properties. Their abrasive resistances, however, are sharply distinguished as illustrated in Table I. If, however, a marked departure from this ratio of 4.221 is made, then a marked change in forgeability and hardenability occurs, the direction and extent of which depends upon the nature and extent of the departure from this ratio.

My researches indicate that when carbon and vanadium appear in the above described excess and ratio they modify the characteristics of the alloy by very desirably augmenting its abrasive resistance without masking or nullifying the other physical characteristics of the basic alloy. I believe that the extraordinary abrasive resistance of my alloy depends upon the formation of vanadium carbides which remain out of solution and accordingly do not affect the hardenability or forgeability of my alloy. While this theory seems to be consistent with observable facts, I do not bind myself thereto. The fact is, that whatever the mechanism may be, the addition of carbon and vanadium in the above described proportions does produce an unexpected and unusual abrasive resistance which is of great technical importance.

While I have described and disclosed the preferred embodiment of my invention, it is to be understood that the invention is not so limited but may be otherwise embodied and practiced within the scope of the following claims.

I claim:

1. An abrasion resisting alloy comprising about 2.3% to 2.6% of carbon, about 12.5% to 13.75% of chromium, about 3% to 5% of vanadium, about 0.2% to 0.6% silicon, about 0.25% to 0.6% manganese, and ,the balance substantially iron with residual impurities in ordinary amounts, in which alloy the vanadium in excess of about 1% is combined with carbon in a ratio of about 4.221.

2. An abrasion resisting alloy comprising about 2.3% to 2.6% of carbon, about 12.5% to 13.75% of chromium, about 3% to 5% of vanadium, about 1% to 1.2% of molybdenum, about 0.2% to 0.6% silicon, about 1.25% to 0.6% manganese, and the balance substantially iron with residual impurities in ordinary amounts, in which alloy the vanadium in excess of.about 1% is combined with carbon in a ratio of about 4.2:1.

3. An abrasion resisting alloy comprising about 2.4% of carbon, about 12.75% chromium, about 4% of vanadium, about 0.4% silicon, about 0.4% manganese, and the balance substantially iron with residual impurities in ordinary amounts,

in'which alloy the vanadium in excess of about 1% is combined with carbon in a ratio of about 42:1.

4. An abrasion resisting alloy comprising about 2.4% of carbon, about 12.75% chromium. about 4% of vanadium, about 1.1% of molybdenum, about 0.4% silicon, about 0.4% manganese, and the balance substantially iron with residual impurities in ordinary amounts, 'in which alloy the vandium in excess of about 1% is combined with carbon in a ratio of about 42:1.

5. An abrasion-resisting alloy having carbon.

in excess of that necessary to give it the desired hardenability characteristics comprising about 2.3% to 2.6% of carbon, about 12.5% to 13.75% of chromium, about 3% to 5% of vanadium, about 0.2% to- 0.6% of silicon, about 0.25% to 0.6% of manganese, and the balance substantially iron with usual residual impurities in ordinary amounts, and in which the concentrations of vanadium and carbon within the given limits are adjusted so that the ratio of vana dium in excess of about 1% to the excess carbon is about 42:1.

6. An abrasion-resisting alloy having carbonin excess of that necessary to give it the desired hardenability characteristics comprising about 2.3% to 2.6% of carbon, about 12.5% to 13.75% of chromium, about 3% to 5% of vanadium. about 1% to 1.2% of molybdenum, about 0.2% to 0.6% of silicon, about 0.25% to 0.60% of manganese, and the balance substantially iron with usual residual impurities in ordinary amounts, and in which the concentrations of vanadium and carbon within the given limits are adjusted so that the ratio of vanadium in excess of about 1% to the excess carbon is about 42:1.

7. An' abrasion-resisting alloy having carbon in excess of that necessary to give it the desired hardenability characteristics comprising about 2.4% carbon, about 12.75% chromium, about 4% vanadiumpabout 0.4% silicon. about 0.4% manganese, and the balance substantially iron with residual impurities in ordinary amounts, in which 'are adjusted so that the ratio of vanadium in excess of about 1% to the'excess carbon is about 4.2:1.

.9. An abrasion resisting article formed from a forgeable abrasion-resisting steel comprising about 2.3% to 2.6% of carbon, about 12.5% to 13.75% of chromium, about 3% to 5% of vanadium, about 1% to 1.2% of molybdenum, about 0.2% to 0.6% silicon, about 0.25% to 0.6% manganese. and the balance substantially iron with residual impurities in ordinary amounts, in which alloy the vanadium in excess of about 1% is combined with carbon in a ratio of about 4.2:1, said article being characterized by high resistance to abrasion and by forging and hardening characteristics comparable to steels having a carbon content a less than that of the article by an amount equal to the per cent vanadium 1% 10. An abrasion-resisting article formed from a iorgeable abrasion-resisting steel comprising about 2.4% carbon, about 12.75% chromium, about 4% of vanadium, about 1.1% o! molybdenum, about 0.4% silicon, about 0.4% manganese, and the balance substantially iron with residual impurities in ordinary amounts, in which alloy the vanadium in excess of about 1% is combined with carbon in a ratio of about 4.2:1, said article being characterized by high resistance to abrasion and by forging and hardening characteristics comparable to steelshaving a carbon content less than that of the article by an amount equal to the per cent vanadium- 1 4.2

11. A brick mold formed of forgeable abrasionresisting steel having carbon in excess of that necessary to give it the desired hardenability characteristics comprising about 2.3% to 2.6% of carbon, about 12.5% to 13.75% of chromium, about 3% to 5% of vanadium, about 0.2% to 0.6% of silicon, about 0.25% to 0.6% of manganese, and the balance substantially iron with usual residual impurities in ordinary amounts, and in which the concentrations of vanadium and carbon within the given limits are adjusted so that ratio of vanadium in excess of about 1% to the excess carbon is about 4.2:1, said brick mold being characterized by high resistance to abrasion 14. An abrasion-resisting alloy having carbon in excess of that necessary to give it the desired hardenability characteristics comprising about 1.3% to 4% 01' carbon, about 11% to 14% chromium, about 3% to 12% vanadium, about 1% maximum manganese, less that 1.5% molybdenum, about 1% maximum silicon, less than 3% nickel, less than 3% tungsten, less than 5% cobalt and the balance substantially iron with residual impurities in ordinary amounts, and in which the concentrations of vanadium and carbon are adjusted so that the ratio of vanadium V in excess of about 1% to the excess carbon is and by forging and hardening characteristics 12. A brick mold or similar abrasion-resisting article formed of abrasion-resisting steel having carbon in excess of that necessary to give it the desired hardenability characteristics containing about 2.3% to 2.6% carbon, about 12.5% to 13.75% of chromium, about 3% to 5% of vanadium, about 1% to 1.2% of molybdenum, about manganese, and the balance substantially iron with usual residual impurities in ordinary amounts, and in which the concentrations of vanadium and carbon within the given limits are about 42:1.

15. An abrasion-resistant article formed of abrasion-resisting steel having carbon in excess of that necessary to give it the desired hardenability characteristics comprising about 1.3% to 4% of carbon, about 11% to 14% chromium, about 3% to 12% vanadium, about 1% maximum manganese, less than about 1.5% molybdenum, about 1% maximum silicon, less than about 3% nickel, less than about 3% tungsten, less than about 5% cobalt and the balance substantially iron with usual residual impurities in ordinary amounts,

and in which the concentrations of vanadium and 1 carbon within the given limits are adjusted so that the ratio of vanadium in excess of about 1% to the excess carbon is about 4.2:1, said article being characterized by high resistance to abrasion and by forging and hardening characteristics comparable to steels having a carboncontent less than that of the article by an amount equal to the per cent vanadium- 1% 4.2

16. A brick mold or similar abrasion-resistant article formed of iorgeable abrasion-resistant steel having carbon in excess of that necessary to give it the desired hardenability characteristics comprising about 1.3% to 4% 01 carbon, about 11% to 14% chromium, about 3% to 12% vanadium, about 1% maximum manganese, less than about 1.5% molybdenum, about 1% maximum silicon, less than about 3% nickel, less than about 3% tungsten, less than about 5% cobalt and the balance substantially iron with usual impurities in ordinary amounts, and in which the concen- 0.2% to 0.6 of silicon, about 0.25% to 0.6% of trations of vanadium and carbon within the given limits are adjusted so that the ratio of vanadium in excess of about 1% to the carbon in excess of that necessary to give the alloy the desired hardenability characteristics is about 4.2: 1, said article adjusted so that the ratio of vanadium in excess being characterized by high resistance to abrasion of about 1% to the excess carbon is about 4.2:1, said brick mold being characterizedby high resistance to abrasion and by forging and hardening characteristics comparable to steels having a carbon content less than that of the article by an amount equal to the per cent vanadium 1 4.2

and by forging and hardening characteristics comparable to steels having a carbon content less than that of the article by an amount equal to the per cent vanadium 1 4.2

17. An abrasion-resistant article formed from an abrasion-resistant steel comprising about 1.3% to 4% carbon, about 11% to 14% chromium, about 3% to 12% vanadium, about 1% maximum manganese, less than about 1.5% molybdenum, about 1% maximum silicon, less than about 3% nickel less than about 3% tungsten, less .-than about 5% cobalt and the balance substantially iron with residual impurities in ordinary amounts,

in'which alloy the vanadium in excess of 1% is combined with carbon in the ratio of 4.2:1, said article being characterized by high resistance to abrasion and by forging and hardening characteristics comparable to steels having a carbon UNITED STATES PATENTS content less than that of the article by an amount Number Name Date equal to the 2,355,726 Harder Aug. 15, 1944 per cent vanadium 1% 5 FOREIGN PATENTS Number Country Date DAVID GILES 693,146 Germany July 4, 194 REFERENCES CITED OTHER REFERENCES 10 Tool Steels, page 380. Edited by Gill et al. The followmg references are of record 1n the Published in 1944 by the American Society for file of this patent:

Metals, Cleveland, Ohio. 

1. AN ABRASION - RESISTING ALLOY COMPRISING ABOUT 2.3% TO 2.6% OF CARBON, ABOUT 12.5% TO 13.75% OF CHROMIUM, ABOUT 3% TO 5% OF VANADIUM, ABOUT 0.2% TO 0.6% SILICON, ABOUT 0.25% TO 0.6% MANGANESE, AND THE BALANCE SUBSTANTIALLY IRON WITH RESIDUAL IMPURITIES IN ORDINARY AMOUNTS, IN WHICH ALLOY THE VANADIUM IN EXCESS OF ABOUT 1% IS COMBINED WITH CARBON IN RATIO OF ABOUT 4.2:1. 